If you've a standard android device that can run vlc, why not just push the files to sd there and play? I've done this for movies on my phone or android tablet, vlc is always good about resuming when used. Kodi as well. If apple lover, who knows, they want you to buy it all from them, and I don't.
I've looked into portable (wifi) media servers, but nothing ever works too well without compromise. Most use local wifi with some local storage, typically sd-based. You can't connect to both it and internet wifi ssid's at same time, and usually the devices are spotty at best. Better sticking to internal flash for media files and using an adequate player to remember where you left off.
Example: I bought a full-size Toshiba SD card with a wifi chip built into it to use it on my 3d printer, to feed files at it, in theory. Seemed nifty, but it was so janky it wasn't worth using. Ymmv using mobile clients with something like that, but I'm usually trying to push from linux or worst-case a windoze vm, and just remember it was hokey to use in any standard fashion.
Chinese crap gadgets mostly these sorts of "sharing" devices, they exist, but usage is always iffy.
-mb